Power point: a nuclear fusion research reactor / GETTY IMAGES
There is no single solution to weaning ourselves from fossil fuels. It requires a combination of unpopular measures, such as lifestyle changes and investment in controversial infrastructure, such as nuclear reactors

Fossil fuels have powered enormous social and economic changes since the Industrial Revolution more than 200 years ago. Energy from coal, oil and natural gas has lit and heated our homes, powered our schools, hospitals and factories, and delivered an abundance of clean water and fresh food for a global population that has grown more than sixfold in two centuries. The developed world gets 80 per cent of its energy from fossil fuels – 90 per cent in Britain – so it’s not surprising we find it hard to contemplate a world without oil.

Yet fossil fuels are a finite resource. The most easily accessible sources have already started to run dry and it will become economically unsustainable to use them on the scales required to meet predicted demand in the coming decades – irrespective of the impact it would have on the climate.

We therefore have to come up with alternative sources of energy, which will almost certainly require a tactical range of policies to cure our addiction to fossil fuels. In this respect, scientists are unanimous on two things. First, no single solution will rid us of our dependency on coal, oil and gas. Second, whatever strategy we choose, implementing it will not be easy. It will require a new way of doing things and possibly some sacrifices in our standards of living.

Britain is legally committed to cutting its greenhouse gas emissions from fossil fuels by 80 per cent by 2050. This cannot be done simply by tweaking a few of the dials on the machinery of our existing energy infrastructure. “Fundamental restructuring of the whole of the UK’s energy system will be unavoidable,” according to the Royal Academy of Engineering in its March 2010 report Generating the Future. “Turning the theoretical emissions-reduction targets into reality will require more than political will: it will require nothing short of the biggest peacetime programme of change ever seen in the UK,” says the academy.

Anyone in any doubt about the scale of the problem we face should read Sustainable Energy – without the hot air by Professor David MacKay, a Cambridge physicist who also happens to be chief scientific adviser at the Department of Energy and Climate Change. Professor MacKay points out that any talk about alternatives to fossil fuels is next to useless unless we can put numbers, rather than meaningless adjectives, to our statements.

It is no good saying, for instance, that you are doing your bit for climate change by turning off the charger to your mobile phone. True, it is better than leaving it on. But when you do the sums, as Professor MacKay has done, then you realise that the amount of energy you save by turning off a mobile phone charger for a day is roughly equivalent to the energy expended in one second by driving a car at an average speed of 50 mph. Switching off your mobile phone charger for a year is roughly the same as the energy used to heat a single hot bath. So, if we are serious about conserving energy, we need to know how much we are saving. While every little helps, Professor MacKay points out “if everybody only does a little, we’ll achieve only a little”.

Saving energy at home and work is an important part of the equation in reducing carbon emissions and cutting down on fossil fuels. When it comes to energy-efficiency schemes, some things make perfect economic sense, like replacing incandescent light bulbs with energy-saving ones. This is why numbers, rather than vague statements, are so important. They enable us to compare one thing against another and make rational decisions on what is the best and easiest thing to do to reduce our dependence on fossil fuels. You might think, for instance, that walking to work rather than driving is a good thing to do in this respect, and you’d be right. But then flying to Cape Town for a holiday would expend the equivalent energy to driving a car 50 km a day, every day for a year.

Numbers matter, says Professor MacKay. Many environmentalists say the UK has huge potential for generating power from renewable sources, such as wind. Professor MacKay says this is a pretty meaningless statement. “It’s not sufficient to know that a source of energy is huge. We need to know how it compares with another ‘huge’, namely our huge consumption. To make such comparisons, we need numbers, not adjectives,” he says.

Britain generates about 4.5 per cent of its electricity from renewable sources of energy, mostly hydro-power, landfill gas and wind. Any substantial increase in renewables – the target is around 20 per cent or higher by 2020 – will involve nationwide projects that will have significant affects on the environment. If, for example, it was decided burning biomass (crops for fuel) in power stations was to be our route to salvation, we would need to cover about 75 per cent of Britain in biomass plantations to meet only 25 per cent of our current energy demand. If we choose wave power, we would need 500 km of Atlantic coastline to be filled with wave

farms. According to Professor MacKay’s calculations, we would need to cover between 5 and 10 per cent of the country with electricity-generating solar panels to provide less than half the daily energy demands of the typical European – about the same energy per person provided by an offshore wind farm filling an area of the sea twice the size of Wales.

“Someone who wants to live on renewable energy, but expects the infrastructure associated with that renewable not to be large or intrusive is deluding himself,” Professor MacKay says. “Such an immense panelling of the countryside and filling of British seas with wind machines (having a capacity five times greater than all the wind turbines in the world today) may be possible according to the laws of physics, but would the public accept and pay for such extreme arrangements?” he asks. “If the answer is no, we are forced to conclude that current consumption will never be met by British renewables. We require either a radical reduction in consumption, or significant additional sources of energy – or, of course, both.”

The holy grail of alternative energy sources is nuclear fusion, where power is generated by fusing atomic nuclei together in a reaction that releases immense amounts of energy. Fusion is the same reaction powering the Sun. It has the advantage over conventional nuclear fission power in that it is clean and virtually waste-free – but it only seems to work at the intensely high temperatures found in the Sun, a problem for a reactor on Earth.

Because of the inherent technological problems in getting nuclear fusion to work, we cannot simply wait for such esoteric, unproven solutions to save us from our energy problem. As the Royal Academy of Engineering says: “There is no more time left for further consultations or detailed optimisation. Equally, there is no time left to wait for new technical developments or innovation. We have to commit to new plant and supporting infrastructure now.”

This is one of the reasons why the Government has committed Britain to a fresh round of building nuclear fission power stations, despite opposition from environmentalists and those concerned about nuclear proliferation. But the science of nuclear power is not in dispute. Nuclear power stations have proven to provide a steady “base load” whether the wind is blowing or the sun is shining, and of course, they do not require fossil fuels – although there is the question about continued supplies of uranium and what to do with the nuclear waste.

Many distinguished scientists have supported nuclear rebuild, saying it is a sensible and viable alternative to dirty coal-fired power stations. They believe they are a critical part of the energy mix that should see us through, hopefully, to the day when nuclear fission reactors are replaced by safer, cleaner nuclear fusion reactors.

Nuclear power, however, is only part of the answer. If the carbon dioxide released from coal-burning power stations could be captured and stored safely underground – so called carbon capture and storage – this would provide another useful weapon in our energy arsenal. But again, the large-scale technology has yet to be proven to be both cheap and reliable. The hope is that it will be ready by 2020, but again this is not certain.

There is no easy solution, no technological fix and no single answer. Weaning ourselves off fossil fuels will require a combination of greater efficiency, changes in habits and lifestyle, and deploying major renewable energy projects that some people will not like. Britain is well suited to generating some of its energy needs from tidal power. Machines operating underwater, and therefore out of sight, could be positioned around the coastline to take advantage of the different times of the day when the tides shift. This would give some variation in energy production throughout the day and night, it would be regular and predictable and sustainable.

But there is another fly in the ointment of this and other alternative energy schemes – it is going to cost money. As the Royal Academy of Engineering says, the most immediate problem facing the UK is to maintain economic growth while fundamentally reconfiguring an electricity generating system that has not changed much in more than 30 years. “This should be possible if barriers to change are removed and the right incentives put in place – but the scale of the challenge should not be underestimated,” says the academy.

Keeping the lights on may seem like a practical and prosaic subject. But, in the words of energy expert Professor Ian Fells, electricity happens to be the lifeblood of civilisation. Without it, we risk a rapid descent into anarchy and barbarism. This is why finding new, sustainable sources of energy is so important to our future well-being, and even to our very existence. m

See our interview with David Hone, with his vision of future energy usage, in a short film produced by Channel 4